qemu-meta: add cmdline to allow input, suggested by James Hogan

target/config/Config.in.target

@@ -6,6 +6,7 @@ config ADK_TARGET_CMDLINE
 	default "fbcon=rotate:1" if ADK_TARGET_SYSTEM_SHARP_ZAURUS
 	default "geodewdt.nowayout=1" if ADK_TARGET_MODEL_PCENGINES_ALIX1C
 	default "kinetis_platform=k70-som" if ADK_TARGET_SYSTEM_KINETIS_K70
+	default "metag_da.console_poll=1" if ADK_TARGET_SYSTEM_QEMU_METAG
 	default ""
 
 choice